*{
    margin: 0;
    padding: 0;
}
a{
    list-style: none;
}
li{
    list-style: none;
}
.lunbo{
    width: 100%;
    padding-bottom: 50px;
    margin-top: 10px;
}
.content{
    width: 1200px;
    height: 400px;
    margin: 20px auto;
    position: relative;
    padding-bottom: 20px;
    padding-top: 10px;
}
#item{
    width: 100%;
    height: 100%;

}
.item{
    position: absolute;
    opacity: 0;
    transition: all 1s;

}
.item.active{
    opacity:1;
}
img{
    width: 100%;
}
#btn-left{
    width: 30px;
    height: 69px;
    font-size: 30px;
    color: white;
    background-color:rgba(0,0,0,0.4);
    line-height: 69px;
    padding-left:5px;
    z-index: 10;/*始终显示在图片的上层*/
    position: absolute;
    left: 0;
    top: 50%;
    transform: translateY(-60%);/*使按钮向上偏移居中对齐*/
    cursor: pointer;
    opacity: 0;/*平时隐藏*/
}
.lunbo:hover #btn-left{
    /*鼠标滑入，显示图标*/
    opacity: 1;
}

#btn-right{
    width: 26px;
    height: 69px;
    font-size: 30px;
    color: white;
    background-color:rgba(0,0,0,0.4);
    line-height: 69px;
    padding-left: 5px;
    z-index: 10;
    position: absolute;
    right: 0;
    top: 50%;
    cursor: pointer;
    opacity: 0;
    transform: translateY(-60%);
}
.lunbo:hover #btn-right{
    opacity: 1;
}
#circle{
    height: 20px;
    display: flex;
    position: absolute;
    bottom: 35px;
    right: 25px;
}
.circle{
    width: 10px;
    height: 10px;
    border-radius: 10px;
    border: 2px solid white;
    background: rgba(0,0,0,0.4);
    cursor: pointer;
    margin: 5px;
}
.white{
    background-color: #FFFFFF;
}


